Heat oil in a pan over medium heat.
Add cumin seeds,Asafoetida and mustard seeds. Let them splutter.
Add chopped ginger-garlic and Sauté for a minute.
Add the finely chopped onions and sauté until translucent.
Mix in turmeric powder, red chili powder, and coriander powder.
Add the diced potatoes Stir to coat with spices.
Add salt to taste and water and mix well.
Cover the pan and cook on medium-low heat. Stir occasionally.
Cook until the potatoes are tender (5-8 minutes)
Add chopped bell peppers cook on medium-low heat. Stir occasionally.
Cook until the potatoes are cooked and the bell peppers are slightly crunchy (5-8 minutes).
Add garam masala, tomatoes and chopped coriander and mix well.
Cook for another 2 minutes.